CA1038650A - Two mass vibratory material handling apparatus and methods of manufacturing and fine tuning the same - Google Patents
Two mass vibratory material handling apparatus and methods of manufacturing and fine tuning the sameInfo
- Publication number
- CA1038650A CA1038650A CA250,536A CA250536A CA1038650A CA 1038650 A CA1038650 A CA 1038650A CA 250536 A CA250536 A CA 250536A CA 1038650 A CA1038650 A CA 1038650A
- Authority
- CA
- Canada
- Prior art keywords
- mass
- vibration
- drive
- attack
- resilient elements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65G—TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS
- B65G27/00—Jigging conveyors
- B65G27/10—Applications of devices for generating or transmitting jigging movements
- B65G27/16—Applications of devices for generating or transmitting jigging movements of vibrators, i.e. devices for producing movements of high frequency and small amplitude
- B65G27/18—Mechanical devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/10—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of mechanical energy
- B06B1/16—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of mechanical energy operating with systems involving rotary unbalanced masses
- B06B1/161—Adjustable systems, i.e. where amplitude or direction of frequency of vibration can be varied
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
- B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
- B07B1/42—Drive mechanisms, regulating or controlling devices, or balancing devices, specially adapted for screens
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/18—Mechanical movements
- Y10T74/18056—Rotary to or from reciprocating or oscillating
- Y10T74/18344—Unbalanced weights
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Jigging Conveyors (AREA)
- Apparatuses For Generation Of Mechanical Vibrations (AREA)
- Measuring Volume Flow (AREA)
- Vibration Prevention Devices (AREA)
- Combined Means For Separation Of Solids (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A two mass vibratory material handling apparatus has a first mass that includes a vibration exciter of the rotary eccentric weight type and a second mass that in-cludes an object to be vibrated. The two masses are inter-connected by resilient elements designed to permit a de-sired vibration amplification from the vibration exciter to the object to be vibrated. The vibration exciter has a drive with an adjustable drive ratio located between a fixed r.p.m. at full voltage motor drive shaft and a shaft that rotatably supports eccentric weights. Variable pitch pulleys or a set of pulleys having various pitch diameters are provided so that pitch diameters can be selected there-from for mounting one pulley on each shaft with a drive belt trained about the pulleys and thus, provide a drive ratio enabling the fixed frequency motor to drive the ec-centric weights at a selected operating frequency. The resilient elements can be designed to amplify vibration along a predetermined line of attack or to flex in that direction while amplifying vibration perpendicularly there-to or to provide a combination of such vibration amplifica-tions to impart an elliptical motion to the second mass.
The apparatus can be manufactured without undue care in maintaining a designed spring rate for the resilient ele-ments or maintaining the designed weight of the two masses since after manufacture and assembly, the apparatus can be fine tuned by weighing the two masses, measuring the ampli-tude of vibration of the mass including the object to be vibrated at a known frequency, selecting an operating fre-quency for obtaining a desired vibration stroke, and adjust-ing the drive ratio to operate at that frequency.
-1a-
A two mass vibratory material handling apparatus has a first mass that includes a vibration exciter of the rotary eccentric weight type and a second mass that in-cludes an object to be vibrated. The two masses are inter-connected by resilient elements designed to permit a de-sired vibration amplification from the vibration exciter to the object to be vibrated. The vibration exciter has a drive with an adjustable drive ratio located between a fixed r.p.m. at full voltage motor drive shaft and a shaft that rotatably supports eccentric weights. Variable pitch pulleys or a set of pulleys having various pitch diameters are provided so that pitch diameters can be selected there-from for mounting one pulley on each shaft with a drive belt trained about the pulleys and thus, provide a drive ratio enabling the fixed frequency motor to drive the ec-centric weights at a selected operating frequency. The resilient elements can be designed to amplify vibration along a predetermined line of attack or to flex in that direction while amplifying vibration perpendicularly there-to or to provide a combination of such vibration amplifica-tions to impart an elliptical motion to the second mass.
The apparatus can be manufactured without undue care in maintaining a designed spring rate for the resilient ele-ments or maintaining the designed weight of the two masses since after manufacture and assembly, the apparatus can be fine tuned by weighing the two masses, measuring the ampli-tude of vibration of the mass including the object to be vibrated at a known frequency, selecting an operating fre-quency for obtaining a desired vibration stroke, and adjust-ing the drive ratio to operate at that frequency.
-1a-
Description
103~
BACKGROIJND OF TE~ TION
Field of the Invention This invention relates to vibratory materialhandling apparatus such as vibrating screens, feeders, conveyors and separators. More particularly, the invention pertains to a vibration exciter drive for a two mass vibratory system and to resilient elements for coupling the two masses.
Description of the Prior Art A vibration exciter drive is shown in United States patent No. 3,703,236 and includes a fixed frequenc~
drive~ motor shaft with a pulley mounted thereon, a rotary eccentric weight shaft with a pulley mounted thereon, and a drive belt trained about the pulleys. ~his drive is incorporated in a two mass vibratory system that includes a vibration exciter mounting having a rectangular tubular frame with elastomeric blocks positioned therein for supporting the vibration exciter. By variation of the number, sizes, placement or compression of the elastomeric blocks, the transmitted vibratory force component in the vertical and horizontal directions can be independently adjusted in order to obtain the desired vibratory motion in the vibrated structure and the desired natural fre-quency of vibration of the vibratory system.
A vibratory material handling apparatus with a rotating eccentric mass driver that is mounted on the apparatus by elastomeric bodies is shown in United States patent ~o. 3,583,553. The driver i5 driven by a fixed frequency motor mounted on the same shaft as the driver.
Work producing vibrations are transmitted along an attack q~--1038~50 axis by compression of the elastomeric bodies while vibratory excursions other than in the direction of such attack axis are dissipated through flexure of the elastomeric bodies in shear. While the vibration exciter force is con-stant, changes in feed rate can result due to var-iations in the head load upon a pile of material to be vibrated.
In conventional two mass vibrating systems it is desirable to have a near resonance operation. Normally, it is not possible to change the operating frequency of the system and there-fore it is necessary to change springs or weights after the system is assembled and operated. Var-lS iations in spring rates due to manufacturingtolerances and variations in trough weight due to both manufacturing tolerances and weight of material to be vibrated require adjustment of the natural frequency of the system for operation at a frequency near resonance level.
SUMMARY OF THE INVENTION
A two mass vibratory material handling apparatus comprises a first mass and a second mass that are interconnected by a plurality of resilient elements. The first mass includes a vibration exciter of the rotary eccentric weight type with an adjustable drive for driv-ing the vibration exciter. The drive has a fixed r.p.m. at full voltage motor with a drive shaft extending from the motor. A driven rotary eccen-,.,.~
'1038650 tric weight shaft extends from the exciter. Afirst pulley is mounted on the drive shaft of the fixed r.p.m. at full voltage motor and a second pulley is mounted on the driven ro-tary eccentric weight shaft. A drive belt istrained about the first pulley and the second pulley. The drive includes means for adjusting the drive ratio of the pulleys to enable the fixed r.p.m. at full voltage motor to drive the driven rotary eccentric weight shaft at a selected operating frequency. The second mass includes a trough for supporting an object to be vibrated within the trough. The second mass to-gether with the object to be vibrated are subject to variations in weight. The resilient elements provide the sole support for the first mass, and these resilient elements have fixed spring rates that influence the natural frequency of vibration for the apparatus in predetermined directions from the vibration exciter to the object to be vibrated.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a broken side elevation view of a vibratory material handling apparatus embodying the present invention.
Figure 2 is a section taken on the line 2-2 of Figure 1.
Figure 3 is a section taken on the line 3-3 of ~,, ,., ,,.~.
- 103~650 Figure 1.
Figure 4 is an exploded view of a set of pulleys having various pitch diameters.
Figure 5 is a broken side elevation view of a modified form of vibratory material handling apparatus embodying the present invention.
Figure 6 is a section taken on the line 6-6 of Figure S.
Figure 7 is a section taken on the line 7-7 of Figure 5.
Figure 8 is a broken side elevation view of a second modified form of vibratory material handling appara-tus embodying the present invention.
Figure 9 is a section taken on the line 9-9 of lS Figure 8.
Figure 10 is a section taken on the line 10-10 of Figure 8.
Figure 11 is a broken side elevation view of a third modified form of vibratory material handling appara-tus embodying the present invention.
- Figure 12 is a section taken on the line 12-12 of Figure 11.
Figure 13 is a section taken on the line 13-13 of Figure 11.
Figure 14 is a partial side elevation view of a variable pitch pulley.
Figure 15 is a section taken on the line lS-15 of Figure 14.
Figure 16 is a graph illustrating the relation between the amplitude of the stroke of the trough and the 1~38650 .
ratio of the driver operating frequency to the trough natural frequency.
DESCRIPTIO~ OF THE PREFERRED EMBODIMEN~S
Looking now at Figures 1-3, a two mass vibratory material handling apparatus 20 such as a bulk material feeder is shown. The first mass includes a vibration exciter or driver having a rotary eccentric weight 21, shown in Figure 2, being mounted upon a shaft 22 that is journalled within bearings 23 and 24 in a vibration exciter housing 25. A pulley 26 is mounted on one end of the shaft projecting outwardly from the housing. An electric motor 27 having a fixed r.p.m. at full line vol-tage is mounted upon the housing. A drive shaft 28 projects from the motor and a pulley 29 is mounted upon the drivè
shaft. A drive belt 30 is trained about the pulleys 26 and 29.
The second mass of the apparatus 20 includes a trough 32 for supporting an object to be vibrated such as bulk granular material M. The trough is suspended from an overhead support, not shown, by vibration isolation springs 33 (only one being shown in Figure 1) that are located near the four corners of the trough and that enable the entire apparatus 20 to vibrate freely without a dampening effect by the support. A pair of vertical plates 34 and 35 having outwardly turned upper flanges 36 and 37, respec-tively, are secured to the bottom of the trough by welding or by fasteners attaching the flanges along each side of the trough bottom with the plates depending therefrom. A
pair of drive plates 38 and 39 extend transversely between the vertical plates at locations fore and aft of the 1038650 ., vibration exciter housing 25. These drive plates are aligned perpendicular to a predetermined line of attack or vibration as indicated by the double arrow 40.
The first and second masses are interconnected between the vibration exciter housing 25 and the foxward drive plate 38 by four steel coil springs 42, as shown in Figures 1 and 3, and between the housing 25 and rearward drive plate 39 by four steel coil springs 43. These steel coil springs are designed to permit a desired vibration amplification from the vibration exciter of the first mass to the object to be vibrated within the second mass. Each steel coil spring has a length to mean diameter ratio that is greater than three and the springs are aligned longitudinally in a direction parallel with the predetermined line of attack as indicated by the double arrow 40. These springs permit a high vibration amplifi-cation axially parallel with the line of attack while providing a relatively low lateral vibration amplificatio~
to permit dissipation of the lateral vibrating forces.
The apparatus 20 can be manufactured by ordinary manufacturing methods with the springs 42 and 43 having spring rates that vary within commonly accepted manufac-turing tolerances, such as plus or minus ten percent. The weight of the trough 32 and the weight of the material M
to be vibrated can also vary over a wide range and such variations can be compensated for after assembly by fine tuning the apparatus as follows: The two masses are weighed separately and after assembly, the amplitude of vibration of the mass including the object to be vibrated is measured at a known frequency. From graphs such as ~03s6so Figure 16 and the known values determined by measurement, an operating frequency for obtaining a desired vibration stroke can be selected. Knowing the operating frequency desired and the fixed r.p.m. at full v~ltage of the elec-tric motor 27, the proper pitch diameters can be deter-mined to provide the drive ratio for driving the eccentric weight 21 at the selected operatin~ frequency.
A pair of pulleys 26 and 29 can be selected to provide the proper drive ratio from a set 44 of pulleys having various pitch diameters, as shown in Figure 4. The selected pulleys are then installed on the shafts 22 and 28 and the apparatus 20 is fine tuned for the desired operation.
Alternately, the pulleys 26 and 29 that are mounted on the shafts 22 and 28 can be of a variable pitch type such as a pulley 26', shown in Figures 14 and 15.
This pulley has a movable flange 45 that fits upon a threaded barrel 46 projecting from a fixed flange 47. By turning the movable flange on the barrel in a clockwise direction, the pitch of the pulley is increased and by turning the movable flange in a counterclockwise direc-tion, the pitch of the pulley is decreased. The pulley pitch is adjustable in half turn increments of the movable flange to vary the width of the tapered slot between coni-cal portions of the flanges. The movable flange is keyedto the barrel by a key 48a that fits within either of two diametrically opposed keyways 48b. The movable flange is locked in place with a locking collar 49 when a desired pitch setting is made. The locking collar has a set screw 49a fitting radially therein to bear upon the key 48a.
~03~
Cap screws 49b and 49c attach the locking collar to the mova~le flange. The threaded barrel 46 is keyed to a shaft 22' by a shear key 46a. ~uch pulleys can be ad-justed to provide the proper drive ratio and the apparatus 20 is fine tuned for the desired operation.
After the tuning operation has been completed, the drive ratio between the motor 27 and the eccentric weight ~1 is constant. Therefore, the operating speed of the driver is directly proportional to the speed of the motor. At full voltage, the motor is at its maximum oper-ating speed or nominal speed, and the operating frequency of the driver is at its maximum frequency or set fre-quency. When the voltage supplied to the motor is reduced, the operating frequency of the driver decreases and the ratio of the driver frequency to the trough natural frequency decreases.
Figure 16 shows the relationship between the amplitude of the stroke of the second mass (trough) and the ratio of the driver operating frequency to the trough natural frequency. As shown in Figure 16, the trough stroke is at its maximum when the driver is operated at the set frequency and the stroke is reduced whenever the driver is operated at any lower frequency. Since the feed rate is proportional to the trough stroke, the operator can select a desired feed rate up to the maximum rate by adjusting the voltage supplied to the motor, thus lowering the motor R.P.M. Means for adjusting the voltage supplied to a motor are well known in the art of motor speed control.
With reference to Figures 5, 6 and 7, a second ~03~6s0 embodiment of the invention is illustrated. by a vibratory material handling apparatus 50. This apparatus differs from the previously described vibratory material handling apparatus 20 in the resilient elements that interconnect the two masses for a desired vibration amplification. In the apparatus 50, a vibration exciter housing 51 has a forward!mounting clamp 52 that is coupled to spaced leaf springs 53 and a rear mounting clamp 54 that is coupled to spaced leaf springs 55. The leaf springs extend transver-sely between vertical plates 56 and. 57 where the ends ofthe springs are clamped in mounting clamp brackets 58 and 59. The leaf springs are arranged to flex in a direction along a predetermined line of attack, as indicated by the double arrow 60 in Figures 5 and 7. If the operating fre-~uency is close to the natural fre~uency in that direction,the vibration amplification will be maximum in that direc-- tion. Since the leaf springs are substantially rigid in a direction perpendicular to the line of attack, as indi-cated by the double arrow 61 in Figure 5, vibration 20 amplification is maximum in this direction.
Looking now at Figures 8, 9 and 10, a third embodiment of the invention is shown by a two mass vibra-tory material handling apparatus 70. This apparatus differs from the previously described vibratory material handling apparatuses 20 and S0 in the resilient elements that interconnect the two masses for a desired vibration amplification. In the apparatus 70, a vibration exciter housing 71 is supported at its forward end by a pair of elastomer or rubber compression springs 72 and 73 that extend axially parallel to a predetermined line of attack _g_ to support a transversely extending mounting plate 74. A
mounting clamp 75 projects forwardly from the mounting plate along the line of attack and is coupled to a pair of transversely extending leaf springs 76. A bracket mount-ing clamp 77 is provided to attach one end of the leafsprings to a vertical plate 78 and a bracket mounting clamp 79 is provided to attach the other end of the leaf springs..to a vertical plate 80.
The rear end of the exciter housing 71 is sup-ported by a pair of elastomer or rubber compression springs82 and 83 that extend axially parallel to a predetermined line of attack to support a transversely extending mounting plate 84. A mounting clamp 85 projects rear-wardly from the mounting plate 84 along the line of . attack and is coupled to a pair of transversely extending leaf springs 86. The ends of the leaf springs are attached to the bracket mounting clamps 77 and 79. The combination of a~ial compression springs and transverse leaf springs together with the ability to select operating frequencies of vibration along the line of attack that are close to the frequencies of vibration perpendicular to the line of attack provides for an elliptical motion on the trough, as indicated by the arrows 87 in Figure 8, and such motion is useful for material agitation in screening or material separation.
Figures 11, 12 and 13 illustrate a fourth em-bodiment of the invention which is incorporated in a two-mass vibratory material handling apparatus 90. This appa-ratus is substantially the same as the previously described apparatus 70 with the exception that four steel 103~650 coil springs 91 have been substituted for the rubber compression springs 72 and 73 and four steel coil springs 92 have been substituted for the rubber compression springs 82 and 83. This spring arrangement can be designed so that the natural frequency in the drive direction (along the line of attack) is near the operating frequency while the natural frequency perpendicular to the line of attack is not close to the operating frequency. This system im-parts nearly linear motion to the second mass and such motion is useful for feeding and conveying. A vibration exciter 93 having high torsional inertias can be used and fine tuned for efficient operation with this spring arrangement.
Thus, the present invention permits adjustment or selection of a drive ratio so that an assembled two mas~ -vibratory material handling apparatus can vibrate at a given percentage of resonance or natural frequency, re-gardless of small variations in spring rates. A wide range of variation in trough weight can be compensated for - 20 by selecting a proper operating frequency and adjusting the drive ratio accordingly. Vibration exciters having high torsional inertias can be used with spring arrangements for imparting an elliptical or linear motion to an object to be vibrated and can be fine tuned for efficient operation.
Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and vari-ation may be made without departing from what is regarded to be the subject matter of the invention.
JWE:csa
BACKGROIJND OF TE~ TION
Field of the Invention This invention relates to vibratory materialhandling apparatus such as vibrating screens, feeders, conveyors and separators. More particularly, the invention pertains to a vibration exciter drive for a two mass vibratory system and to resilient elements for coupling the two masses.
Description of the Prior Art A vibration exciter drive is shown in United States patent No. 3,703,236 and includes a fixed frequenc~
drive~ motor shaft with a pulley mounted thereon, a rotary eccentric weight shaft with a pulley mounted thereon, and a drive belt trained about the pulleys. ~his drive is incorporated in a two mass vibratory system that includes a vibration exciter mounting having a rectangular tubular frame with elastomeric blocks positioned therein for supporting the vibration exciter. By variation of the number, sizes, placement or compression of the elastomeric blocks, the transmitted vibratory force component in the vertical and horizontal directions can be independently adjusted in order to obtain the desired vibratory motion in the vibrated structure and the desired natural fre-quency of vibration of the vibratory system.
A vibratory material handling apparatus with a rotating eccentric mass driver that is mounted on the apparatus by elastomeric bodies is shown in United States patent ~o. 3,583,553. The driver i5 driven by a fixed frequency motor mounted on the same shaft as the driver.
Work producing vibrations are transmitted along an attack q~--1038~50 axis by compression of the elastomeric bodies while vibratory excursions other than in the direction of such attack axis are dissipated through flexure of the elastomeric bodies in shear. While the vibration exciter force is con-stant, changes in feed rate can result due to var-iations in the head load upon a pile of material to be vibrated.
In conventional two mass vibrating systems it is desirable to have a near resonance operation. Normally, it is not possible to change the operating frequency of the system and there-fore it is necessary to change springs or weights after the system is assembled and operated. Var-lS iations in spring rates due to manufacturingtolerances and variations in trough weight due to both manufacturing tolerances and weight of material to be vibrated require adjustment of the natural frequency of the system for operation at a frequency near resonance level.
SUMMARY OF THE INVENTION
A two mass vibratory material handling apparatus comprises a first mass and a second mass that are interconnected by a plurality of resilient elements. The first mass includes a vibration exciter of the rotary eccentric weight type with an adjustable drive for driv-ing the vibration exciter. The drive has a fixed r.p.m. at full voltage motor with a drive shaft extending from the motor. A driven rotary eccen-,.,.~
'1038650 tric weight shaft extends from the exciter. Afirst pulley is mounted on the drive shaft of the fixed r.p.m. at full voltage motor and a second pulley is mounted on the driven ro-tary eccentric weight shaft. A drive belt istrained about the first pulley and the second pulley. The drive includes means for adjusting the drive ratio of the pulleys to enable the fixed r.p.m. at full voltage motor to drive the driven rotary eccentric weight shaft at a selected operating frequency. The second mass includes a trough for supporting an object to be vibrated within the trough. The second mass to-gether with the object to be vibrated are subject to variations in weight. The resilient elements provide the sole support for the first mass, and these resilient elements have fixed spring rates that influence the natural frequency of vibration for the apparatus in predetermined directions from the vibration exciter to the object to be vibrated.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a broken side elevation view of a vibratory material handling apparatus embodying the present invention.
Figure 2 is a section taken on the line 2-2 of Figure 1.
Figure 3 is a section taken on the line 3-3 of ~,, ,., ,,.~.
- 103~650 Figure 1.
Figure 4 is an exploded view of a set of pulleys having various pitch diameters.
Figure 5 is a broken side elevation view of a modified form of vibratory material handling apparatus embodying the present invention.
Figure 6 is a section taken on the line 6-6 of Figure S.
Figure 7 is a section taken on the line 7-7 of Figure 5.
Figure 8 is a broken side elevation view of a second modified form of vibratory material handling appara-tus embodying the present invention.
Figure 9 is a section taken on the line 9-9 of lS Figure 8.
Figure 10 is a section taken on the line 10-10 of Figure 8.
Figure 11 is a broken side elevation view of a third modified form of vibratory material handling appara-tus embodying the present invention.
- Figure 12 is a section taken on the line 12-12 of Figure 11.
Figure 13 is a section taken on the line 13-13 of Figure 11.
Figure 14 is a partial side elevation view of a variable pitch pulley.
Figure 15 is a section taken on the line lS-15 of Figure 14.
Figure 16 is a graph illustrating the relation between the amplitude of the stroke of the trough and the 1~38650 .
ratio of the driver operating frequency to the trough natural frequency.
DESCRIPTIO~ OF THE PREFERRED EMBODIMEN~S
Looking now at Figures 1-3, a two mass vibratory material handling apparatus 20 such as a bulk material feeder is shown. The first mass includes a vibration exciter or driver having a rotary eccentric weight 21, shown in Figure 2, being mounted upon a shaft 22 that is journalled within bearings 23 and 24 in a vibration exciter housing 25. A pulley 26 is mounted on one end of the shaft projecting outwardly from the housing. An electric motor 27 having a fixed r.p.m. at full line vol-tage is mounted upon the housing. A drive shaft 28 projects from the motor and a pulley 29 is mounted upon the drivè
shaft. A drive belt 30 is trained about the pulleys 26 and 29.
The second mass of the apparatus 20 includes a trough 32 for supporting an object to be vibrated such as bulk granular material M. The trough is suspended from an overhead support, not shown, by vibration isolation springs 33 (only one being shown in Figure 1) that are located near the four corners of the trough and that enable the entire apparatus 20 to vibrate freely without a dampening effect by the support. A pair of vertical plates 34 and 35 having outwardly turned upper flanges 36 and 37, respec-tively, are secured to the bottom of the trough by welding or by fasteners attaching the flanges along each side of the trough bottom with the plates depending therefrom. A
pair of drive plates 38 and 39 extend transversely between the vertical plates at locations fore and aft of the 1038650 ., vibration exciter housing 25. These drive plates are aligned perpendicular to a predetermined line of attack or vibration as indicated by the double arrow 40.
The first and second masses are interconnected between the vibration exciter housing 25 and the foxward drive plate 38 by four steel coil springs 42, as shown in Figures 1 and 3, and between the housing 25 and rearward drive plate 39 by four steel coil springs 43. These steel coil springs are designed to permit a desired vibration amplification from the vibration exciter of the first mass to the object to be vibrated within the second mass. Each steel coil spring has a length to mean diameter ratio that is greater than three and the springs are aligned longitudinally in a direction parallel with the predetermined line of attack as indicated by the double arrow 40. These springs permit a high vibration amplifi-cation axially parallel with the line of attack while providing a relatively low lateral vibration amplificatio~
to permit dissipation of the lateral vibrating forces.
The apparatus 20 can be manufactured by ordinary manufacturing methods with the springs 42 and 43 having spring rates that vary within commonly accepted manufac-turing tolerances, such as plus or minus ten percent. The weight of the trough 32 and the weight of the material M
to be vibrated can also vary over a wide range and such variations can be compensated for after assembly by fine tuning the apparatus as follows: The two masses are weighed separately and after assembly, the amplitude of vibration of the mass including the object to be vibrated is measured at a known frequency. From graphs such as ~03s6so Figure 16 and the known values determined by measurement, an operating frequency for obtaining a desired vibration stroke can be selected. Knowing the operating frequency desired and the fixed r.p.m. at full v~ltage of the elec-tric motor 27, the proper pitch diameters can be deter-mined to provide the drive ratio for driving the eccentric weight 21 at the selected operatin~ frequency.
A pair of pulleys 26 and 29 can be selected to provide the proper drive ratio from a set 44 of pulleys having various pitch diameters, as shown in Figure 4. The selected pulleys are then installed on the shafts 22 and 28 and the apparatus 20 is fine tuned for the desired operation.
Alternately, the pulleys 26 and 29 that are mounted on the shafts 22 and 28 can be of a variable pitch type such as a pulley 26', shown in Figures 14 and 15.
This pulley has a movable flange 45 that fits upon a threaded barrel 46 projecting from a fixed flange 47. By turning the movable flange on the barrel in a clockwise direction, the pitch of the pulley is increased and by turning the movable flange in a counterclockwise direc-tion, the pitch of the pulley is decreased. The pulley pitch is adjustable in half turn increments of the movable flange to vary the width of the tapered slot between coni-cal portions of the flanges. The movable flange is keyedto the barrel by a key 48a that fits within either of two diametrically opposed keyways 48b. The movable flange is locked in place with a locking collar 49 when a desired pitch setting is made. The locking collar has a set screw 49a fitting radially therein to bear upon the key 48a.
~03~
Cap screws 49b and 49c attach the locking collar to the mova~le flange. The threaded barrel 46 is keyed to a shaft 22' by a shear key 46a. ~uch pulleys can be ad-justed to provide the proper drive ratio and the apparatus 20 is fine tuned for the desired operation.
After the tuning operation has been completed, the drive ratio between the motor 27 and the eccentric weight ~1 is constant. Therefore, the operating speed of the driver is directly proportional to the speed of the motor. At full voltage, the motor is at its maximum oper-ating speed or nominal speed, and the operating frequency of the driver is at its maximum frequency or set fre-quency. When the voltage supplied to the motor is reduced, the operating frequency of the driver decreases and the ratio of the driver frequency to the trough natural frequency decreases.
Figure 16 shows the relationship between the amplitude of the stroke of the second mass (trough) and the ratio of the driver operating frequency to the trough natural frequency. As shown in Figure 16, the trough stroke is at its maximum when the driver is operated at the set frequency and the stroke is reduced whenever the driver is operated at any lower frequency. Since the feed rate is proportional to the trough stroke, the operator can select a desired feed rate up to the maximum rate by adjusting the voltage supplied to the motor, thus lowering the motor R.P.M. Means for adjusting the voltage supplied to a motor are well known in the art of motor speed control.
With reference to Figures 5, 6 and 7, a second ~03~6s0 embodiment of the invention is illustrated. by a vibratory material handling apparatus 50. This apparatus differs from the previously described vibratory material handling apparatus 20 in the resilient elements that interconnect the two masses for a desired vibration amplification. In the apparatus 50, a vibration exciter housing 51 has a forward!mounting clamp 52 that is coupled to spaced leaf springs 53 and a rear mounting clamp 54 that is coupled to spaced leaf springs 55. The leaf springs extend transver-sely between vertical plates 56 and. 57 where the ends ofthe springs are clamped in mounting clamp brackets 58 and 59. The leaf springs are arranged to flex in a direction along a predetermined line of attack, as indicated by the double arrow 60 in Figures 5 and 7. If the operating fre-~uency is close to the natural fre~uency in that direction,the vibration amplification will be maximum in that direc-- tion. Since the leaf springs are substantially rigid in a direction perpendicular to the line of attack, as indi-cated by the double arrow 61 in Figure 5, vibration 20 amplification is maximum in this direction.
Looking now at Figures 8, 9 and 10, a third embodiment of the invention is shown by a two mass vibra-tory material handling apparatus 70. This apparatus differs from the previously described vibratory material handling apparatuses 20 and S0 in the resilient elements that interconnect the two masses for a desired vibration amplification. In the apparatus 70, a vibration exciter housing 71 is supported at its forward end by a pair of elastomer or rubber compression springs 72 and 73 that extend axially parallel to a predetermined line of attack _g_ to support a transversely extending mounting plate 74. A
mounting clamp 75 projects forwardly from the mounting plate along the line of attack and is coupled to a pair of transversely extending leaf springs 76. A bracket mount-ing clamp 77 is provided to attach one end of the leafsprings to a vertical plate 78 and a bracket mounting clamp 79 is provided to attach the other end of the leaf springs..to a vertical plate 80.
The rear end of the exciter housing 71 is sup-ported by a pair of elastomer or rubber compression springs82 and 83 that extend axially parallel to a predetermined line of attack to support a transversely extending mounting plate 84. A mounting clamp 85 projects rear-wardly from the mounting plate 84 along the line of . attack and is coupled to a pair of transversely extending leaf springs 86. The ends of the leaf springs are attached to the bracket mounting clamps 77 and 79. The combination of a~ial compression springs and transverse leaf springs together with the ability to select operating frequencies of vibration along the line of attack that are close to the frequencies of vibration perpendicular to the line of attack provides for an elliptical motion on the trough, as indicated by the arrows 87 in Figure 8, and such motion is useful for material agitation in screening or material separation.
Figures 11, 12 and 13 illustrate a fourth em-bodiment of the invention which is incorporated in a two-mass vibratory material handling apparatus 90. This appa-ratus is substantially the same as the previously described apparatus 70 with the exception that four steel 103~650 coil springs 91 have been substituted for the rubber compression springs 72 and 73 and four steel coil springs 92 have been substituted for the rubber compression springs 82 and 83. This spring arrangement can be designed so that the natural frequency in the drive direction (along the line of attack) is near the operating frequency while the natural frequency perpendicular to the line of attack is not close to the operating frequency. This system im-parts nearly linear motion to the second mass and such motion is useful for feeding and conveying. A vibration exciter 93 having high torsional inertias can be used and fine tuned for efficient operation with this spring arrangement.
Thus, the present invention permits adjustment or selection of a drive ratio so that an assembled two mas~ -vibratory material handling apparatus can vibrate at a given percentage of resonance or natural frequency, re-gardless of small variations in spring rates. A wide range of variation in trough weight can be compensated for - 20 by selecting a proper operating frequency and adjusting the drive ratio accordingly. Vibration exciters having high torsional inertias can be used with spring arrangements for imparting an elliptical or linear motion to an object to be vibrated and can be fine tuned for efficient operation.
Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and vari-ation may be made without departing from what is regarded to be the subject matter of the invention.
JWE:csa
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A two mass vibratory material handling appa-ratus comprising a first mass, a second mass, and a plurality of resilient elements that interconnect the first and second masses, said first mass including a vibra-tion exciter of the rotary eccentric weight type with an adjustable drive for driving the vibration exciter, said drive including a fixed r.p.m. at full voltage motor with a drive shaft extending therefrom, a driven rotary eccen-tric weight shaft extending from the exciter, a first pulley mounted on the drive shaft of the fixed r.p.m. at full voltage motor, a second pulley mounted on the driven rotary eccentric weight shaft, and a drive belt trained about the first and second pulleys, said drive including means for adjusting the drive ratio of the pulleys to enable the fixed r.p.m. at full voltage motor to drive the driven rotary eccentric weight shaft at a selected opera-ting frequency, said second mass including a trough for supporting an object to be vibrated within the trough, said second mass together with the object to be vibrated being subject to variations in weight, said resilient elements providing the sole support for said first mass, said resilient elements having fixed spring rates that influence the natural frequency of vibration for the appa-ratus in predetermined directions from the vibration ex-citer to the object to be vibrated.
2. A two mass vibratory material handling appa-ratus according to claim 1 wherein said resilient elements have a plurality of steel coil springs located between the vibration exciter and the second mass, said coil springs being aligned longitudinally in a direction parallel with a predetermined line of attack and having a length to mean diameter ratio greater than three.
3. A two mass vibratory material handling appa-ratus according to claim 1 wherein said resilient elements have a plurality of leaf springs arranged to flex in a direction along a predetermined line of attack and to pro-vide a substantially rigid coupling between the masses in a direction perpendicular to the line of attack.
4. A two mass vibratory material handling appa-ratus according to claim 1 wherein said resilient elements have a combination of leaf springs arranged to flex in a direction along a predetermined lone of attack and steel coil springs aligned longitudinally along the line of attack.
5. A two mass vibratory material handling appa-ratus according to claim 1 wherein said resilient elements have a combination of leaf springs arranged to flex in a direction along a predetermined line of attack and rubber compression springs aligned longitudinally along the line of attack.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/610,593 US4040303A (en) | 1975-09-05 | 1975-09-05 | Two mass vibratory material handling apparatus and methods of manufacturing and fine tuning the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1038650A true CA1038650A (en) | 1978-09-19 |
Family
ID=24445658
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA250,536A Expired CA1038650A (en) | 1975-09-05 | 1976-04-20 | Two mass vibratory material handling apparatus and methods of manufacturing and fine tuning the same |
Country Status (13)
| Country | Link |
|---|---|
| US (1) | US4040303A (en) |
| JP (2) | JPS5233278A (en) |
| AT (1) | AT353170B (en) |
| AU (1) | AU497578B2 (en) |
| BE (1) | BE845706A (en) |
| BR (1) | BR7604148A (en) |
| CA (1) | CA1038650A (en) |
| DE (1) | DE2623761C2 (en) |
| ES (1) | ES451205A1 (en) |
| FR (1) | FR2322669A1 (en) |
| GB (1) | GB1562233A (en) |
| NL (1) | NL161691C (en) |
| ZA (1) | ZA762399B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4218929A (en) * | 1977-12-29 | 1980-08-26 | Syn-Energy, Inc. | Vibratory device for feeders and the like |
| US4754870A (en) * | 1982-08-12 | 1988-07-05 | Litton Systems, Inc. | Two mass vibrating feeder |
| US4795552A (en) * | 1987-04-24 | 1989-01-03 | Telsmith, Inc. | Natural frequency vibrating screen |
| ATE133919T1 (en) * | 1991-08-12 | 1996-02-15 | Pillsbury Co | DEVICE FOR FEEDING OBJECTS |
| US6298978B1 (en) | 2000-05-01 | 2001-10-09 | Carrier Vibrating Equipment, Inc. | Reversing natural frequency vibratory conveyor system |
| US20040075203A1 (en) * | 2002-10-16 | 2004-04-22 | Cable Jeffrey L. | Vibratory machines utilizing ovoid or rectangular shaped coil drive springs |
| DE102006041989B4 (en) * | 2006-09-07 | 2009-06-04 | Paul Gmbh & Co. Kg | Sieving machine especially for difficult to separate mixtures, such as heavy oil-sand mixtures |
| CN101773908B (en) * | 2010-03-08 | 2011-12-14 | 南京工程学院 | Multistage eccentric block exciter |
| CN101972740A (en) * | 2010-10-08 | 2011-02-16 | 南京工程学院 | Two-stage moving-pendulum chaos exciter |
| US9101959B2 (en) * | 2012-04-27 | 2015-08-11 | Martin Engineering Company | Vibratory device with repositionable weights and method of extending the useful life of vibratory devices |
| DE102012214341A1 (en) * | 2012-08-10 | 2014-05-15 | Vibra Maschinenfabrik Schultheis Gmbh & Co. | Treatment device for pourable bulk material |
| US9038491B2 (en) * | 2013-05-06 | 2015-05-26 | Martin Engineering Company | Method of repositioning bearing wear in an industrial eccentric weight vibrator via power inversion and vibrator therefore |
| US11318429B2 (en) * | 2017-03-06 | 2022-05-03 | Northeastern University | Enclosed mixture stirrer using intermittent resonance and method |
| CN114278703B (en) * | 2021-12-30 | 2024-03-15 | 哈尔滨工程大学 | Low-frequency quasi-zero stiffness vibration isolator integrated by double-geometric nonlinear structure |
| CN118635112B (en) * | 2024-08-12 | 2024-11-22 | 四川省凤鸣茶业有限公司 | Multi-stage screening device and method for green tea processing |
Family Cites Families (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE559231A (en) * | ||||
| US2133593A (en) * | 1936-12-24 | 1938-10-18 | Herbert E Tautz | Variable speed drive |
| US2517328A (en) * | 1948-02-10 | 1950-08-01 | John G Lownsbery | Multispeed attachment for electric motors and the like |
| US2958228A (en) * | 1956-10-24 | 1960-11-01 | Chain Belt Co | Resonant vibration exciter |
| US3040591A (en) * | 1958-11-07 | 1962-06-26 | British Steel Piling Co Ltd | Impulse vibrators |
| US2984339A (en) * | 1959-07-06 | 1961-05-16 | Chain Belt Co | Tunable vibratory apparatus |
| US3089582A (en) * | 1960-12-19 | 1963-05-14 | Gen Kinematics Corp | Vibratory device |
| US3387499A (en) * | 1964-09-02 | 1968-06-11 | Beteiligungs & Patentverw Gmbh | Mechanical vibrator with electromagnetic damping means |
| DE1301922B (en) * | 1965-10-26 | 1969-08-28 | Rex Chainbelt Inc | Device for operating a vibratory work device |
| DE1558839A1 (en) * | 1967-04-28 | 1970-06-11 | Jordan Dr Ing Heinz | Vibratory drive using two self-synchronizing counter-rotating imbalances |
| FR1531291A (en) * | 1967-07-19 | 1968-06-28 | Badische Maschf Gmbh | Dynamic oscillating system for actuating an oscillating mass as a working device and dynamic oscillating machine therefor |
| CH511645A (en) * | 1968-08-23 | 1971-08-31 | Huber Ernst | Vibration exciter for machines with a vibrating work tank |
| US3583553A (en) * | 1968-11-29 | 1971-06-08 | Fmc Corp | Vibratory material handling apparatus |
| US3682254A (en) * | 1970-07-06 | 1972-08-08 | Regus Ag | Spring-loaded hammer |
| US3703236A (en) * | 1970-07-31 | 1972-11-21 | Fmc Corp | Vibrator mounting |
| DE2127433B2 (en) * | 1971-06-03 | 1973-05-30 | Grimmer, Klaus Jürgen, Dr Ing , 4720 Beckum | UNBALANCE EXCITER FOR DRIVING A VIBRATING CHANNEL OR VIBRATING SCREEN |
| JPS5247687Y2 (en) * | 1971-06-10 | 1977-10-29 | ||
| JPS4841747U (en) * | 1971-09-22 | 1973-05-28 | ||
| JPS4938358A (en) * | 1972-08-24 | 1974-04-10 |
-
1975
- 1975-09-05 US US05/610,593 patent/US4040303A/en not_active Expired - Lifetime
-
1976
- 1976-04-15 AU AU13036/76A patent/AU497578B2/en not_active Expired
- 1976-04-20 CA CA250,536A patent/CA1038650A/en not_active Expired
- 1976-04-22 ZA ZA762399A patent/ZA762399B/en unknown
- 1976-05-26 DE DE2623761A patent/DE2623761C2/en not_active Expired
- 1976-06-09 NL NL7606206.A patent/NL161691C/en not_active IP Right Cessation
- 1976-06-14 AT AT433176A patent/AT353170B/en not_active IP Right Cessation
- 1976-06-25 BR BR7604148A patent/BR7604148A/en unknown
- 1976-08-11 JP JP51095001A patent/JPS5233278A/en active Pending
- 1976-08-31 BE BE170236A patent/BE845706A/en unknown
- 1976-09-03 FR FR7626635A patent/FR2322669A1/en active Granted
- 1976-09-03 ES ES451205A patent/ES451205A1/en not_active Expired
- 1976-09-04 GB GB19507/76A patent/GB1562233A/en not_active Expired
-
1981
- 1981-05-20 JP JP56076395A patent/JPS57126309A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| AT353170B (en) | 1979-10-25 |
| ATA433176A (en) | 1979-03-15 |
| NL161691B (en) | 1979-10-15 |
| FR2322669B1 (en) | 1982-06-11 |
| US4040303A (en) | 1977-08-09 |
| ES451205A1 (en) | 1977-09-16 |
| AU497578B2 (en) | 1978-12-21 |
| NL7606206A (en) | 1977-03-08 |
| DE2623761C2 (en) | 1986-02-13 |
| DE2623761A1 (en) | 1977-03-17 |
| AU1303676A (en) | 1977-10-20 |
| JPS57126309A (en) | 1982-08-06 |
| JPS5233278A (en) | 1977-03-14 |
| NL161691C (en) | 1980-03-17 |
| ZA762399B (en) | 1977-04-27 |
| GB1562233A (en) | 1980-03-05 |
| BR7604148A (en) | 1977-07-26 |
| BE845706A (en) | 1976-12-16 |
| FR2322669A1 (en) | 1977-04-01 |
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